Since Xcode 4.2 Apple doesn’t ship a normal GCC anymore, but instead packages LLVM. While it was possible to compile Ruby with LLVM before, the result was error prone. Not anymore! Since 1.9.3-p125 Ruby is fully compatible with LLVM and here is how you can install it without the need of any additional GCC installation.

I’m going to use rbenv and ruby-build in the progress. This way everything is installed in ~/.rbenv and you won’t need any administrator privileges.